:root {
  --bg: #f6f3ee;
  --bg-elev: #fffdf9;
  --ink: #1c1915;
  --muted: #5c564c;
  --line: #d9d0c3;
  --accent: #0f6b5c;
  --accent-ink: #083d35;
  --focus: #c45c26;
  --mono: "IBM Plex Mono", "SF Mono", ui-monospace, monospace;
  --sans: "Source Serif 4", "Iowan Old Style", "Palatino Linotype", Palatino, serif;
  --ui: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --max: 46rem;
  --radius: 10px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141210;
    --bg-elev: #1c1916;
    --ink: #f3eee6;
    --muted: #b0a79a;
    --line: #3a342c;
    --accent: #5ec4b0;
    --accent-ink: #b8ebe0;
    --focus: #e08a55;
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 10% -10%, color-mix(in srgb, var(--accent) 18%, transparent), transparent),
    radial-gradient(900px 400px at 100% 0%, color-mix(in srgb, var(--focus) 12%, transparent), transparent),
    var(--bg);
  font-family: var(--sans);
  line-height: 1.55;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--bg-elev);
  color: var(--ink);
  padding: 0.5rem 0.75rem;
  z-index: 10;
}

.skip-link:focus {
  left: 0.5rem;
  top: 0.5rem;
}

.top {
  position: sticky;
  top: 0;
  z-index: 5;
  display: grid;
  gap: 0.75rem;
  padding: 0.85rem 1.1rem;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg-elev) 92%, transparent);
  backdrop-filter: blur(10px);
}

.top__brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.top__title {
  font-family: var(--ui);
  font-weight: 650;
  letter-spacing: -0.02em;
  color: var(--ink);
  text-decoration: none;
  font-size: 1.05rem;
}

.top__badge {
  font-family: var(--ui);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent-ink);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.15rem 0.55rem;
  background: var(--bg);
}

.top__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 0.85rem;
  font-family: var(--ui);
  font-size: 0.92rem;
}

.top__nav a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  padding-bottom: 0.1rem;
}

.top__nav a:hover,
.top__nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--accent);
}

.top__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.btn {
  font-family: var(--ui);
  font-size: 0.85rem;
  border: 1px solid var(--line);
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  padding: 0.4rem 0.75rem;
  cursor: pointer;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
}

@media (prefers-color-scheme: dark) {
  /* Mid teal (#5ec4b0) + white fails WCAG AA; use deeper fill for primary actions. */
  .btn:not(.btn--ghost) {
    background: #0f6b5c;
    border-color: #0f6b5c;
    color: #fff;
  }
}

.btn--ghost {
  background: transparent;
  color: var(--ink);
}

.btn:focus-visible,
.top__nav a:focus-visible,
.top__title:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.content {
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.5rem 1.15rem 3rem;
}

.content .loading {
  color: var(--muted);
  font-family: var(--ui);
}

.content h1,
.content h2,
.content h3 {
  font-family: var(--ui);
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.content h1 {
  font-size: clamp(1.7rem, 3vw, 2.2rem);
  margin: 0 0 1rem;
}

.content h2 {
  margin-top: 2rem;
  padding-top: 0.4rem;
  border-top: 1px solid var(--line);
}

.content a {
  color: var(--accent-ink);
}

.content code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: color-mix(in srgb, var(--line) 35%, transparent);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

.content pre {
  overflow-x: auto;
  padding: 0.9rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--bg-elev);
  font-family: var(--mono);
  font-size: 0.82rem;
}

.content pre code {
  background: none;
  padding: 0;
}

.content table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--ui);
  font-size: 0.92rem;
  margin: 1rem 0 1.4rem;
}

.content th,
.content td {
  border: 1px solid var(--line);
  padding: 0.45rem 0.55rem;
  vertical-align: top;
  text-align: left;
}

.content th {
  background: color-mix(in srgb, var(--line) 28%, transparent);
}

.content blockquote {
  margin: 1rem 0;
  padding: 0.2rem 0 0.2rem 0.9rem;
  border-left: 3px solid var(--accent);
  color: var(--muted);
}

.content .mermaid {
  margin: 1.25rem 0;
  padding: 0.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--bg-elev);
  overflow-x: auto;
}

.content ul.contains-task-list {
  list-style: none;
  padding-left: 0;
}

.content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--bg-elev);
  margin: 0.75rem 0 1.25rem;
}

.foot {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.15rem 2rem;
  color: var(--muted);
  font-family: var(--ui);
  font-size: 0.85rem;
}

.toast {
  position: fixed;
  right: 1rem;
  bottom: 1rem;
  background: var(--ink);
  color: var(--bg);
  font-family: var(--ui);
  font-size: 0.85rem;
  padding: 0.55rem 0.8rem;
  border-radius: 8px;
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 0.2s, transform 0.2s;
  pointer-events: none;
}

.toast.show {
  opacity: 1;
  transform: translateY(0);
}

@media (min-width: 900px) {
  .top {
    grid-template-columns: 1fr auto auto;
    align-items: center;
  }
}